This invention relates to brake systems for vehicles, and more particularly to brake boosters for such systems.
A typical brake system for a vehicle includes a brake booster, which is used to amplify the force applied directly to a brake pedal by an operator of the vehicle. The booster is typically mounted outside of the passenger compartment in the engine compartment on a firewall, or dashboard, forming the front wall of the passenger compartment. A push rod extends from the booster through an opening in the front wall for connection with a brake pedal assembly located within the passenger compartment. A flexible boot, or a sliding seal is provided around the push rod for environmentally sealing the hole in the front wall while allowing movement of the push rod by the brake pedal.
The booster is mounted in this fashion because it must draw in and expel a volume of air through a breather port surrounding the push rod, as the brake pedal is depressed and released. This drawing in and expulsion of air through the breather port unavoidably generates noise that would be objectionable to passengers in the vehicle, if the booster were mounted within the passenger compartment. Because the breather port surrounding the push rod is located on the side of the booster closest to the front wall of the passenger compartment, some provision must be made to allow air to flow between the booster and the front wall, in order for the air around the booster to reach the breather port.
In some prior booster mounting arrangements, a mounting adapter is provided between the booster and the front wall of the passenger compartment. The adapter includes a ventilation port open to the engine compartment to provide airflow through the adapter to and from the breather port of the booster. For example, U.S. Pat. No. 4,932,275 provides an adapter that significantly increases the distance the booster protrudes into the engine compartment. In another approach, the housing of the booster on its side adjacent the front wall of the passenger compartment is formed to provide an air channel, such that when the booster is mounted on the wall, air can flow through the channel from the engine compartment to the booster breather port. German patent application DE 195 23 309 A1 discloses this approach.
The present invention is a spacer for separating a brake booster from a wall. The spacer comprises a support and a boot. The support is disposed between the booster and the wall, and has a breather port. The boot is integral with the support, and has a generally conical shape tapering from the wall toward a push rod of the booster.
Accordingly, it is an object of the present invention to provide a spacer of the type described above that suppresses noise in the passenger compartment during application of the brakes.
Another object of the present invention is to provide a spacer of the type described above in which the boot is integral with the support.
Another object of the present invention is to provide a brake booster, including a spacer of the type described above, that is relatively simple, reliable, light weight and cost effective.
The foregoing and other features and advantages of the invention are apparent from the following detailed description of exemplary embodiments, read in conjunction with the accompanying drawings. The detailed description and drawings are merely illustrative of the invention rather than limiting, the scope of the invention being defined by the appended claims and equivalents thereof.